Recommendations

1. That Model 2 presents best available science for the 2021 Patagonian toothfish stock assessment in Division 58.5.2.
2. That CCAMLR set a catch limit of 3010 tonnes for 2021/22 and 2022/23 in CM 41-08 based on the result of this assessment and the CCAMLR decision rules.

Abstract

This paper presents an updated assessment for the Patagonian toothfish (Dissostichus eleginoides) fishery at Heard Island and McDonald Islands (HIMI) in CCAMLR Division 58.5.2 with catch until the end of 2021 and observations until the end of 2020. The updated assessment model is based on best available estimates of model parameters, the use of abundance estimates from a random stratified trawl survey (RSTS), longline tag-release data from 2012-2019 and longline tag-recapture data from 2013-2020, and auxiliary commercial composition data to aid with the estimation of year class strength and selectivity functions of the trawl, longline and trap sub-fisheries.

Compared to the 2019 assessment that was accepted by WG-FSA-19 to be used for management advice, this assessment takes into account (1) update the model with catch data to 2021 and observations to the end of 2020 including new ageing data from the RSTS and commercial fishery, and (2) updated growth parameters. All model runs were conducted with the CASAL version 2.30-2012-03-21 rev. 4648 that was agreed on by WG-SAM-14.

The estimates of this stock assessment were similar to those from the 2019 assessment (Ziegler 2019a). The updated assessment model led to a slightly smaller estimate of the virgin spawning stock biomass B₀ than that obtained in 2019, with an MCMC estimate of 69 210 tonnes (95% CI: 64 811-74 758 tonnes). The estimated SSB status at the end of 2021 was 0.45 (95% CI: 0.44-0.47), in line with the projection from the 2019 stock assessment.

The comprehensive monitoring program of the HIMI toothfish fishery will continue to include a tag-recapture program, annual trawl surveys, and extensive fish ageing to consolidate and estimate recent trends in biomass and YCS.

Based on the result of this assessment and the CCAMLR decision rules, we recommend that CCAMLR set a catch limit of 3010 tonnes for 2021/22 and 2022/23 in CM 41-08 for the Patagonian toothfish fishery in Division 58.5.2.

Recommendations

We recommend the catch limits in Conservation Measure 42-02 be set at 1528 t in the 2021/22 season and 1138 t in the 2022/23 season.

Abstract

The annual random stratified trawl survey was undertaken in Division 58.5.2 in the vicinity of Heard Island and McDonald Islands during April 2021. Based on data from this survey, this paper provides a preliminary assessment for mackerel icefish (Champsocephalus gunnari) population structure, abundance and yield in Division 58.5.2 using standard CCAMLR methods (CMIX and Generalized Yield Model).

The 2021 survey showed a large 3+ cohort in the population and a high biomass. Based on the Grym implementation, catches of 1528 t in the 2021/22 season and 1138 t in the 2022/23 season satisfy the CCAMLR decision rules.

During late March to mid-April 2021, the annual random stratified trawl survey (RSTS) around Heard Island and McDonald Islands (HIMI) was conducted in CCAMLR Division 58.5.2, with the completion of 163 stations. The survey was conducted for the first time on the Cape Arkona. Sampling protocols such as the design and the duration of the hauls were similar to recent surveys, but with a new set of randomly selected station points.

The catch of Patagonian toothfish (Dissostichus eleginoides) was 77.9 t – the second highest catch since the RSTS began.  The catch of mackerel icefish (Champsocephalus gunnari) was 35.7 t which represents an almost 5-fold increase in catch from 2020.

Biomass estimates for the managed by-catch species unicorn icefish (Champsocephalus rhinoceratus) showed a steady increase in catch whereas grey rockcod (Lepidonotothen squamifrons) was relatively similar to last year and the catch of Macrourus spp. has declined.  All three species of skate were caught in lower numbers than has been the case in recent years.

Length and weight measurements were taken for 21,712 fish with additional biological measurements recorded for about half of these individuals.  Otoliths were collected from 161 D. eleginoides and 116 L. squamifrons.

Ce document passe en revue les activités du secrétariat au cours de la période 2020–2021 en faisant le point sur la dotation en personnel et la mise en œuvre du plan stratégique 2019–2022. La Commission et le Comité scientifique doivent noter que le secrétariat élaborera début 2022 un nouveau plan stratégique et de dotation en personnel pour couvrir les années 2023–2026 et sont priés de fournir une assistance supplémentaire au secrétariat dans le cadre de ce processus.

Conformément à une décision du SCAF (SCAF-38, paragraphe 48), le présent document contient les termes de référence et le modèle de convention de financement relatifs au fonds de renforcement des capacités scientifiques générales (FCSG).

This paper provides a summary of the operation of the fishery forecasting algorithm for the Ross Sea toothfish fisheries for WG-FSA-2021, reviews the forecasting algorithm for fishery closures in the 2019/20 and 2020/21 fishing seasons, and considers alternative scenarios. The secretariat considers that the implementation of the forecasting procedures in place were consistent with the objective of avoiding exceed the catch limits, but some improvements to the algorithm can be discussed to improve its accuracy.

Robust stock assessments and catch limits for Dissostichus mawsoni according to CCAMLR decision rules remain to be determined for Divisions 58.4.1 and 58.4.2. Precautionary management arrangements are in place as set out in Conservation Measures 41-11 and 41-05.

WG-FSA-16/29, WG-FSA-18/59, WG-FSA-19/44, and SC-CAMLR-39/BG/10 outlined the multi-member toothfish exploratory fishery research plans for these Divisions, including the research objectives, methods, and milestones in accordance with ANNEX 24-01/A.

In this paper we report on (1) exploratory fishing activities undertaken by Australia, France, Japan, the Republic of Korea, and Spain between the 2011/12 and 2020/21 fishing seasons (fishing seasons are hereafter abbreviated to the end year), as per Milestone 1.7 and (2) ageing of collected toothfish otoliths and updated estimation of biological parameters as per Milestone 1.8.

The summaries provided herein were generated using an R-Markdown document that is available to Members to facilitate standardised reporting on data collection in CCAMLR’s Exploratory Fisheries.